Action Mailer Problem with salted hash login generator

Hi! Guys
I am using the salted hash login generator for login purpose. Now, I
am working in friendship. When I want to request someone for
friendship request via the action mailer I get following error:

Due to changes in ActionMailer, you need to provide the mailer_name
along with the template name.

render “user_mailer/signup”
render :file => “user_mailer/signup”

If you are rendering a subtemplate, you must now use controller-like
partial syntax:

render :partial => ‘signup’ # no mailer_name necessary

As I am new to rails, I don’t get what it really means. So plz…
help me.